1. T suppressor cell function is subnormal when MS is active, and B- adrenergic receptors are up-regulated on T suppressor cells from MS patients with progressive disease. B-interferon corrects suppressor cell function in MS at least in vitro. We will determine whether B-adrenergic agonists and immune globulin also correct suppressor function. 2. Muscarinic acetylcholine receptors are up-regulated on CD4+ T cells in progressive MS and possibly on CD8+ T cells. We will determine the status of acetylcholine receptors in stable MS and during MS attacks and the effects of cholinergic ligands on lymphocyte function in MS. 3. Avid SRBC-binding T cells are reduced in progressive MS. T cell proliferation triggered by the 9.6 mAb to CD2 protein is reduced in MS. SRBC bind to CD2. We will determine if there is a structural change in CD2 in MS.] 4. Production of cytokines by monocytes is increased in MS. We will attempt to abrogate this response with B-adrenergic agonists. 5. gamma-IFN causes attacks of MS. The effect of gamma-IFN on T suppressor cell function of cells from stable MS cases will be determined. We postulate that MS cells may be inordinately sensitive to gamma-IFN.